A method for hiding information utilizing double-random phase-encoding technique

A method for hiding information is proposed. Firstly, the image to be hidden is encoded by the doubled-random phase-encoding technique. Then, the real part of the encoded data, together with the imaginary part, is embedded into a sufficiently large host image, which has been enlarged according to some rules. The superposition weighting is adjusted to a proper value such that the composed image will not be subject to severe degradation compared to the original host image. When decryption is needed, the reconstructed hidden image can be extracted directly from the composed image without using original host image, with the result being quite satisfactory. The quality of the reconstructed hidden image and of the composed image has been analyzed as the superposition weight varies, allowing the determination of the optimum superposition weight. The optimum superposition weight is related to the average gray level value of the hiding image.